This invention has to do with applicators useful for applying surgical prep liquids to the skin.
The conventional preparation of a patient's skin for surgery includes an extended period of cleaning using soap or the like, followed by the application of an antiseptic or disinfectant. The nature, duration and difficulty of this task depend heavily on the kind of surgical procedure to be followed, and on the size, shape and orientation of the body parts involved.
The oldest—and still widespread—method of applying the disinfectant is by dipping a swab, sponge or pad, held in forceps, into a dish of liquid and wiping it over the skin. Spent swabs/pads are continually discarded and fresh ones taken. The disinfectant is usually alcohol-based and may contain ingredients (such as iodine) that can irritate or burn the skin. It is important that the rate of application of solution be controlled, so that excess does not flow away to unintended areas, or form pools underneath the body or in hollows of the body where it may burn or irritate the patient, or indeed be a fire hazard if a cauterisation procedure is used. It is generally desirable to avoid mess or spillage whether on the patient's body or elsewhere. Another reason for keeping the applied liquid under control is to avoid liquid which has contacted one region of the patient's skin flowing away (or being carried on the applicator) so that it then contacts another region.
Conversely, and despite all the above factors indicating careful application, surgical prep is often done under severe time pressure and subject to safety and effectiveness there is every interest in doing it as quickly as possible.
Over the years many proposals have been made for hand-held applicator devices for applying surgical prep solution, incorporating an applicator head with a pad, sponge or other soft or deformable permeable element to be wiped across the skin, and a reservoir of the surgical prep solution—often contained in a handle of the device—communicating with the applicator pad to feed solution. This can make the application more efficient by obviating the repeated dipping of swabs and the discarding and replacement of spent swabs. By providing the solution in a sealed sterile reservoir or cartridge, which can be opened by engaging it appropriately with an applicator head (e.g. by a spike built into the applicator head rupturing a membrane or film closure on the front of the cartridge) operation of these devices is made easy. Nevertheless these are devices which, although used under time pressure and needing to be reliable, must be of simple and economical construction since they may be used only once. With these constraints, it has been quite difficult to produce a cost-effective device with which the application of prep solution to the skin is really controllable and convenient while being adaptable to different preferences of surgeons and their assistants. There is much room for improvements to be made.
In the present disclosure, we address issues of distributing liquid flow to a permeable, deformable applicator member such as a sponge element, and of controlling the flow between a liquid supply reservoir and the permeable applicator element.
As regards distribution of flow, WO2006/041801 describes an applicator having a flat permeable applicator pad on the front face of a distributor element which provides sub-divided chambers behind the pad, each chamber receiving prep solution from the reservoir.
U.S. Pat. No. 4,415,288 has an applicator sponge block exposed on both oppositely-directed major faces, receiving liquid from the handle reservoir along a conduit with an enlarged perforated end chamber embedded in the centre of the sponge block. An alternative has a flat paddle-shaped projection into the sponge interior, with a liquid feed to each face of the paddle from a hole adjacent its root.
WO01/74436 discloses a flat rectangular sponge pad with a back face fixed to a flat rectangular spreader plate the same size as the pad. Solution enters through a central hole of the spreader plate, which has a pattern of radiating channels on its front face to assist flow towards the edges of the back of the foam pad. A small film pad may be positioned in front of the central opening, to encourage outward flow along the channels.
U.S. Pat. No. 4,925,327 suggests inserting a porous layer over the rear surface of the applicator pad.